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Pregled bibliografske jedinice broj: 452468

Kinetics and Mechanism of Oxidation of Hydroxyurea with Hexacyanoferrate( III) Ions in Aqueous Solution


Budimir, Ana; Bešić, Erim; Biruš, Mladen
Kinetics and Mechanism of Oxidation of Hydroxyurea with Hexacyanoferrate( III) Ions in Aqueous Solution // Croatica chemica acta, 82 (2009), 4; 807-818 (međunarodna recenzija, članak, znanstveni)


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Naslov
Kinetics and Mechanism of Oxidation of Hydroxyurea with Hexacyanoferrate( III) Ions in Aqueous Solution

Autori
Budimir, Ana ; Bešić, Erim ; Biruš, Mladen

Izvornik
Croatica chemica acta (0011-1643) 82 (2009), 4; 807-818

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
hydroxyurea; hexacyanoferrate(III); kinetics; redox reaction; oxidation; mechanism

Sažetak
Hydroxyurea (HU) effectively reduces Fe(CN)6 3− to Fe(CN)6 4− species in neutral and basic aqueous solution via an electron transfer process that includes the formation and subsequent fading out of a free radical, U• (U• ≡ H2N−C(=O)N(H)O•). The EPR spectrum of U• in H2O solutions suggests that the unpaired electron is located predominantly on the hydroxamate hydroxyl-oxygen atom. Visible spectrophotometric data reveal HU as a two-electron donor. Stoichiometry of the studied reaction can be formulated as: 2Fe(CN)6 3− + NH2CONHOH + ½H2O  2Fe(CN)6 4− + CO2 + NH3 + ½N2O + 2H+. Lack of evidence for the formation of NO probably is a consequence of fast dimerization of HNO in comparison with the rate of its oxidation, which is slow due to the low reduction potential of the Fe(CN)6 3−/ Fe(CN)6 4− couple. The kinetic of oxidation of HU by Fe(CN)6 3− was studied using stopped-flow technique, as a function of H+, HU, Fe(CN)6 3− and Fe(CN)6 4− concentrations, as well as a function of ionic strength and temperature. The kinetic results reveal that oxidation of HU by Fe(CN)6 3− proceed via an outer-sphere electron-transfer process. The effect of ionic strength on the reaction rate reveals that NaFe(CN)6 2− is the reacting species rather than Fe(CN)6 3− ion. The rate of the redox process was found to be first order with respect to both redox reactants while the H+ concentration dependence make clear that U− is about four orders of magnitude more reactive than HU. The formal reduction potentials for U•/U− and HU•/HU couples were estimated from the kinetic results as +0.47 V and +0.84 V, respectively.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

Napomena
Rad je kao poster prezentiran na skupu 28th International Conference on Solution Chemistry. održanom od 23.-28.09.2003., Debrecen, Mađarska ; objavlejn u Knjizi sazetaka ; Lazar, Istvan ; Toth, Imre (ur.) ; 2003 ; str. 130-130.



POVEZANOST RADA


Projekt / tema
0006441
006-0061247-0009 - Kinetika i mehanizam katalitičkog antioksidacijskog djelovanja Mn-porfirina (Ana Budimir, )

Ustanove
Farmaceutsko-biokemijski fakultet, Zagreb

Profili:

Avatar Url Erim Bešić (autor)

Avatar Url Ana Budimir (autor)

Avatar Url Mladen Biruš (autor)

Citiraj ovu publikaciju

Budimir, Ana; Bešić, Erim; Biruš, Mladen
Kinetics and Mechanism of Oxidation of Hydroxyurea with Hexacyanoferrate( III) Ions in Aqueous Solution // Croatica chemica acta, 82 (2009), 4; 807-818 (međunarodna recenzija, članak, znanstveni)
Budimir, A., Bešić, E. & Biruš, M. (2009) Kinetics and Mechanism of Oxidation of Hydroxyurea with Hexacyanoferrate( III) Ions in Aqueous Solution. Croatica chemica acta, 82 (4), 807-818.
@article{article, year = {2009}, pages = {807-818}, keywords = {hydroxyurea, hexacyanoferrate(III), kinetics, redox reaction, oxidation, mechanism}, journal = {Croatica chemica acta}, volume = {82}, number = {4}, issn = {0011-1643}, title = {Kinetics and Mechanism of Oxidation of Hydroxyurea with Hexacyanoferrate( III) Ions in Aqueous Solution}, keyword = {hydroxyurea, hexacyanoferrate(III), kinetics, redox reaction, oxidation, mechanism} }

Časopis indeksira:


  • Current Contents Connect (CCC)
  • Web of Science Core Collection (WoSCC)
    • Science Citation Index Expanded (SCI-EXP)
    • SCI-EXP, SSCI i/ili A&HCI
  • Scopus